Months ago I purchased a French expansion table. I painted the table legs white and I am refinishing the top and expansion pieces in a dark stain with a semi gloss poly finish (Minwax). I noticed when I initially stripped this table that one section didn't strip well. I had to strip it again.
That stripping did well but when I put the poly on it, it was very cloudy and streaked. Attributed it to the poly being outside in the Louisiana heat and humidity and not giving the can time to acclimate to indoor temperatures (as it was poly'ed indoors). So went back and stripped it a third time.
This particular time, Minwax told me that I didn't give the stain enough time to dry as this coat of poly was tacky and didn't dry. Furthermore, there were streaks in the finish. So they suggested Mineral Spirits. I used it and it did help. But after sanding to try and remove the streaks, I could see scratches in the finish and I was so upset I stripped it again.
So, here I am on the fourth stripping. This time I took my time. I hand sanded the piece. I stained it and waited two days before putting the first coat of poly. Being I had had so much trouble with the poly before on this piece, I used a sponge applicator thinking it would make a difference. These streaks are what I am left with. It was a little tacky the next day but it's almost dry. The streaks are back!!! I'm scared to sand it because last time I did that it scratched the table top even though I used the correct grit as indicated on the can.
So, to recap, poly acclimated correctly to room temperature, stain set for 48 hours. What am I doing wrong? How do I fix this so I can move on with my life?
Best Answer
As Harper mentions old poly can be a problem, but poly that is not well mixed (stirred not shaken) can also be an issue. If you sand you may well have scratches but don’t strip again--you need more coats and a very fine sand paper or fine steel wool between coats for best results.
I have put more than a dozen coats of poly down for a gorgeous finish. Depending on wood type and the time of year I may wait 2 weeks after staining to start putting down poly. Have I ever stopped at 1 coat? Yes but not often--my “quick” quality jobs are usually 3 coats looks very nice. And with the right conditions can be done in 1 day but usually 2.
Just a note I like wet sandpaper at 600 grit for multiple coats and have gone up to 1200 grit in the past for an absolute perfect finish.
What do I mean about stirred not shaken? Stirring will mix the poly without introducing air bubbles like shaking will. I do shake on occasion but have a vacuum pot to pull the air bubbles out. I can’t tell if your haze is surface or below, over working poly will cause a haze to form those pesky air bubbles. In some cases it helps to thin the poly on the first coat or two if the haze is because of grain. 1-2 maybe 3 brush strokes and move on or you will create the haze by over working the poly.
Lastly, use a very nice brush. I have brushes that cost $15-20. After use I clean them in solvent, then seal them in a jar of fresh solvent. I like solvent-based poly because I have used it for over 40 years and this method preserves the brushes. I think I am close to 7 years on the same brushes and they are almost new looking. I hope this helps.